Extending the applicability of Cryo-EM for fragile biological systems via ultra-pure cryo-samples from Preparative Native Mass Spectrometry

2026-07-22

Precise structural, conformational, as well as chemical information of biological molecules forms the basis for comprehension and control of biological processes, including metabolism, pathological processes, and drug targeting. Cryo-electron microscopy (cryo-EM) has evolved into one of the leading methods for structural characterisation of folded proteins and protein complexes reaching atomic resolution through averaging. Thus, the unambiguous assignment of thousands of images to different oligomers, conformers, and fragments is a key requirement for high-resolution single particle cryo-EM. However, reliable preparation of homogeneous cryo samples remains one of, if not the, most important challenge in cryo-EM. Native mass spectrometry (native MS) allows to retain proteins in a near native state in an ultrapure gas-phase molecular ion-beam, providing complementary information on mass, composition, conformation and ligand binding sites. Preparative mass spectrometry (prep-MS) is able to generate ultrapure samples by soft landing of mass- and conformation selected molecules on surfaces for subsequent analysis. Here, we propose to implement preparative native mass spectrometry (pnMS), combining the strengths of native MS, prep-MS, and cryo-EM, to establish a new versatile pathway for comprehensive structural analysis of biological systems. We will design ion optics to couple a mass selected molecular ion beam from a commercial high-performance MS and a landing stage to add deposition capability. Initial experiments will focus on benchmark systems such as BSA and GroEL, before approaching more challenging proteins, including heat shock proteins (HSPs) and G-Protein coupled receptors (GPCRs). Ultimately, pnMS should enable the structural biology community to obtain a comprehensive understanding of structural variety (proteoforms), protein interactions (interactome), and synthetic structures, e.g. needed for customised medicine.

United Kingdom (UK)

2026-02-15